Shock absorbing device for the yarn carrier rods in flat knitting machines of the cotton type



C. MAZET Sept. 15, 1959 I SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT 1 KNITTING MACHINES OF THE COTTON TYPE Filed July 1, 1958 l4 Sheets-Sheet 1 2,903,870 ARRIER RODS IN FLAT C. MAZET YARN C THE COTTON TY Sept. 15,- 1959 SHOCK ABSORBING DEVICE THE KNITTING MACH ES OF PE Filed July 1, 1958 14 Sheets-Sheet 2 III-Ill Ill 7"! all Sept. 15, 1959 c. 'MAZET SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE'COTTON TYPE l4 Sheets-Sheet 3 Filed July 1. 1958 c. MAZET 2,903,870 DEVICE FOR YARN CARRIER RODS IN FLAT THE COTTON TYPE Sept. 15, 1959 SHOCK ABSORBI NG KNITTING MACHINES Fiied July 1, 1958 14 Sheets-Sheet 4 Sept. 15, 1959 c. MAZET 2,903,870

-SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE 1 l4 Sheets-Sheet 5 Filed July 1, 1958 p 15, 1959 c. MAZET 2, 0 ,870

SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed July 1, 1958 14 Sheets-Sheet 6 Fig. 15 Fig. 14

91 as 77 7a 79 92 55 23 Sept. 15, 1959 c. MAZET 2,903,870

SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE l4 Sheets-Sheet 7 Filed July 1, 1958 c. MAZET 2,903,870

YARN CARRIER RODS IN FLAT THE COTTON TY Sept. 15, 1959 SHOCK ABSORBING DEVICE FOR THE KNITTING MACHINES OF PE Filed July 1, 1958 l4 Sheets-Sheet 8 Sept. 15,.1959 c. MAZET 2,903,870

' snocx ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed July 1, 195a 14 Sheets-Sheet 9 die Sept. 15, 1959 c. MAZET 2,903,870

. SHOCK ABSORBING DEVICE FOR THEYARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed Julyvl, 1958 v 14 Sheets-Sheet 10 Sept. 15, 1959 c. MAZET SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed July 1', 1958 14 Sheets-Sheet 11 Sept. 15, 1959 c. MAZET 2,903,370

SHOCK ABSORBING DEVICE FOR THE YARN. CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed July 1, '1958' 14 Sheets-Sheet l2 c. MAZ'ET Sept. 15, 1959 2,903,870 'SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE 14 Sheets-Sheet l3 Fi led July 1, 1958 Sept. 15, 1959 c. MAZET 2,903,870

SHOCK ABSORBING DEVICE FOR THE YARN CARRIER RODS IN FLAT KNITTING MACHINES OF THE COTTON TYPE Filed July 1, 1958 14 Sheets-Sheet 14 United States Patent SHOCK ABSORBING DEVICE FOR THE YARN CAR- RIER RODS 1N FLAT KNITTING MACHINES OF THE COTTON TYPE Charles Mazet, Ganges, Herault, France Application July 1, 1958, Serial No. 745,872

Claims priority, application France July 11, 1957 12 Claims. (Cl. 66-130) My invention has for its object the damping of the movements of the yarn carrier rods in flat knitting machines of the Cotton type.

In flat knitting machines of the Cotton type, the shifting of the yarn carrier rods is often ensured through the agency of so-called friction boxes, driven by a friction box rod assuming a longitudinal translational movement. As disclosed hereinafter, the operation of these friction boxes leads to considerable trouble and their upkeep is a delicate matter and requires continuous attention.

To cut out these drawbacks, a number of builders of knitting frames have proposed frictionless driving means for the yarn carrier rods as provided for instance by a member such as an arresting dog or a link positively connected with the yarn carrier rod.

Unfortunately, whereas such arrangements allow cutting out the defects inherent to friction boxes, they show other defects which are inherent thereto and are without remedy. in fact, they cannot satisfy in a general manner all the conditions required for the driving of the yarn carrying rods, chiefly in the case of travels of a reduced length to be executed by the latter for instance for splicing and for executing stocking toes. Furthermore, they are comparatively brittle and they require often auxiliary parts such as sinker cams so as to start the yarn carriers before the jack sinkers.

To this end, I have endeavoured to cut out the defects of friction operated systems which actually show unlimited possibilities of application since they allow limiting the travel of a yarn carrier rod to any predetermined length through the operation of a suitable end stop.

This advantage allows resorting to a single type of carrier motion for the different yarn carrier rods used in Cotton machines.

My invention has therefore for its object a shock absorbing device for the yarn carrier rods in flat knitting machines wherein the movement of the rods is ensured through friction boxes.

In order to allow my invention to be more readily understood, I will first disclose briefly the conditions of operation of the conventional shock absorbing devices associated with friction box control means.

When the yarn carrier rod engages its stop at the end of its stroke, the friction box stops and slides over the friction box rod, the movement of which continues for a short time after said stoppage of the yarn carrier rod.

In order to avoid a sudden stoppage of the yarn carrier rod when impinging against its stop, arrangements are provided for damping the end of the travel of the yarn carrier rod. To this end and as illustrated in Fig. 20 of the accompanying drawings, there is a moment 1 towards the end of the travel of the yarn carrier rod for which the friction box engages a damping stop which assumes a positively controlled damped movement and this results in that, from said .moment t onwards, the

'ice

friction box assumes the same damped movement until the moment T2 at which the yarn carrier rod impinges against its end stop. Two damping stops are provided respectively at the right end side and at the left end side of the travel of the yarn carrier rod.

Such a shock absorbing device is characterized by the following points:

(1) The moments T1 and T2 corresponding respectively to the beginning and to the end of the operative movement of the damping stop are defined for each sinking operation by the positions of the stops to be engaged by the yarn carrier rod. The damping of the movement of the yarn carrier rod is therefore complete if the moment t at which the friction box comes into contact with the damping stop is the same as the moment T1 at which both parts have substantially equal speeds.

To this end, it is necessary to satisfy the following conditions:

(a) It is necessary for the positions of the stops for the yarn carrier rod to be symmetrical with reference to the center of the knitting head; said necessity does not allow consequently using such shock absorbing means for the yarn carrying rods used for splicing purposes;

(b) It is necessary for the friction box to be prevented from sliding over the friction box rod during the sinking of the thread up to the moment T1; it is diflicult to satisfy this condition in practice.

In practice, the moment t is always later than the moment T1. Fig. 20 is a graph showing the distances travelled over as a function of time.

The curve on drawn in solid lines illustrates the shiftof the friction box rod, the movement being uniformly accelerated at the beginning and uniformly damped towards its end; between said extreme moments, the spec assumes a constant value.

The solid line curve ocb illustrates the theoretical shifting of the yarn carrier rod, assuming there is no sliding during the sinking of the thread. The point 0 of this curve defines the beginning of the damping and corresponds to the moment T1, the point b of the curve corresponding to the end of the damping at the moment T2.

The curve c-a'b drawn as a line of dashes illustrates the actual shifting of the yarn carrier rod with some sliding of the friction box during the sinking. The damping is incomplete and the friction box engages suddenly the damping stop at the point d of the curve which corresponds to the moment t.

The curve 0-e illustrated as a dotted line shows the shifting of the yarn carrier rod with a sliding of the friction box during the sinking of the yarn carrier rod, which sliding is larger than precedingly. The yarn carrier rod impinges suddenly against its stop at a moment t later than T2.

(2) The shifting of the damping stop is, through its actual design, of a constant length whatever may be the position of the end stops for the yarn carrier rods. Consequently, the shock absorber cannot be used when the stroke of the yarn carrier rod is smaller than the shifting of the damping stop.

My invention has for its object to provide a shock absorbing device for a yarn carrier rod, which does not show the above-mentioned drawbacks of conventional arrangements controlled through friction boxes.

T 0 this end and according to my invention, the shock absorbing device is of the type including chiefly two shock absorbing or damping members, to wit: a cam adapted to pivot round an axis perpendicular to the direction of movement of the friction box rod and a stop member adapted to cooperate with said cam when the friction box reaches a point near the end of its travel,

one of said members being carried by the friction box and the other by a part of the frame which is rigid with the corresponding stop for the yarn carrier rod. According to my invention, the cam is urged into rotation by the pressure exerted between it and the stop member while the movement of said cam is braked by an auxiliary friction box mounted on a friction box rod moving in synchronism with the above-mentioned friction box bar, the outline of the cam being such that the speed of the main friction box may be reduced and become preferably substantially equal to zero when said main friction box reaches the end of its stroke together with the yarn carrier rod. i

Under such conditions, Fig. 21 which is a graph of the distances travelled over as a function of time for an arrangement according to my invention as defined hereinabove, shows a curve oa drawn in solid lines to illustrate the movement of the friction box rod, the beginning of which movement is uniformly accelerated and the end of which is uniformly damped while the speed is constant between said beginning and said end.

The curve fh drawn in solid lines shows the theoretical shifting of the yarn carrier rod, without taking into account any sliding of the friction during the sinking of the thread. The point 1 of said curve defines the beginning of the damping and corresponds to the point E1 of the travel by the yarn carrier rod. The point h 'of the curve considered defines the end of the damping and corresponds to the point E2 of the travel executed by the yarn carrier rod.

The curve 0ij drawn asa line of dashes illustrates the movement of the yarn carrier rod for a certain sliding of the friction box during the sinking of the thread; the damping i is complete and is obtained between the points E1 and E2 of the travel of the yarn carrier rod.

v The curve 0-k-l drawn as a dotted line illustrates the shifting of the yarn carrier rod with a sliding of the friction box which is larger than precedingly. The damp ing k-l is again complete and is obtained as precedingly between the points E1 and E2 of the travel of the yarn carrier rod.

My improved shock absorbing device executed in accordance with the principle disclosed shows therefore the following advantages:

I (1) The damping is constant whatever may be the sliding of the friction box during the sinking of the thread. The frame may operate with friction boxes which are more yielding and which become hot more slowly and to a lesser extent. The linings of the friction shoes may benefit by a longer life and the friction box will strain to a lesser extent the friction box stops and the stops for the yarn carrier rods.

(2) The damping obtained depends solely on the stop :against which the friction box is to impinge and this leads to the two following consequences: I

(a) The shock absorbing device may be used with friction boxes carrying along with them yarn carrier rods serving for reinforcing or splicing purposes;

(b) The shock absorbing device disclosed may be used without any risk of breaking any part, even when the and by no means in a limiting sense two preferred embodiments of my invention. In said drawings:

Fig. 1 is a partial transverse vertical cross-section of a knitting machine of the Cotton type which incorporates a first embodiment of my invention for damping the friction box carrying along with it the yarn carrier rod.

Fig. 2 is a perspective view of the arrangement includng the shock absorbing device and the parts cooperatng therewith.

Fig. 3 is a view of the rear end of the shock absorbing device during a sinking performed from the right hand side towards the left hand side.

Fig. 4 is a plan view corresponding to Fig. 3.

Fig. 5 is a partial sectional view through line V-V of Fig. 13.

Figs. 6 to 12 show different stages of operation of the shock absorbing device at the end of each sinking opera tion during an ordinary knitting procedure.

Fig. 13 is a plan view of the device adapted for use with a splicing stop.

Figs. 14 to 17 show different stages of the operation of the device when used for splicing purposes.

Figs. 18 to 21 are explanatory drafts to some of which reference has been made hereinabove.

Fig. 18 is a graph showing the movements of the driving friction box as a function of time for two different adjustments of the relative clamping of the two friction boxes on the friction box rod.

Fig. 19 is a draft showing the relative position of the different parts of the shock absorbing device during operation of the latter.

Fig. 20 is the graph already referred to, showing as a function of time the distances travelled over by the friction box of the carrier motion in conventional shock absorbing devices.

Fig. 21 is a similar graph also referred to precedingly corresponding to the shock absorbing device according to my invention.

Fig. 22 is a front view of a second embodiment of the shock absorbing device according to my invention.

Fig. 23 is a corresponding plan view.

Figs. 24 and 25 are views similar to Fig. 22 for two further positions of the device.

Most of the above figures show the device as seen from the rear, so that the parts described as lying to the left are illustrated on the right hand side and reversely.

Referring first to the general perspective view drawn in Fig. 2, the yarn carrier 1 for a knitting machine of the Cotton type is carried by a yarn carrier rod 2 adapted to slide longitudinally under the action of a driving dog 3 one end of which is fitted inside a notch 4 of a square shaped member 5 rigidly secured to said yarn carrier rod 2. At the end of its stroke, the yarn carrier rod 2 impinges against the head of a screw 7 engaging a stop 8 locked by means of a safety nut 9 (Fig. 4).

The driving'dog 3 is pivotally secured to a spindle 11 carried inside a mortise 12 formed in the upper surface of a main friction box 13 carried by a friction box rod 14 assuming a longitudinal reciprocatory movement in accordance with the conventional technique of such Cotton frames. The means for fitting the friction box 13 on said friction rod 14 are irrelevant and may be obtained, e.g. as illustrated in Fig. 5, by two shoes 15 lined with small leather plates 16 and capped by a stirrup shaped member 17 set inside the friction box 13 as illustrated in Fig. 5. The two arms of the stirrup shaped member 17 are connected by a stay 18 inside which is fitted a pressure-adjusting screw 19 adapted to be locked by a safety nut 20 and to adjust the adherence between the friction box and its rod. A blade spring 21 provides for stability of this adjustment.

A damping lever 23 forming a cam is pivotally secured to' a short spindle 24 screwed inside a boss 25 rigid with the driving friction box 13. The damping lever 23 includes an extension 26 and inside its extension there-is screwed a short spindle 27 over which is fitted a ring 28. Said ring 28 serves as a support for a coaxial locking roller 29 and for the head of a connecting rod 31, the other end of which is fitted over a spindle 32 screwed into'aboss 33 rigid with an auxiliary friction box '34 fitted over the friction box rod 14 in a manner similar to that disclosed with reference to the main friction box '13 (Fig.2).

symmetrical with reference to the straight line connecting the center A of the spindle 24, with the center B of the spindle 27 (Fig. 9). Said outline includes a half circumference 11 having A for its center and extending into two straight lines JK and IN parallel with the straight line AB and terminating with two arcuate concave sections KL and NM of which the centers are shown at U and V respectively.

The arrangement includes also two two-arm locking levers, to wit: the left-hand locking lever 37 and the right-hand locking lever 38. The left-hand locking lever 37 pivots round a spindle 41 screwed into a boss 42 of the driving section box 13. The upper arm of said lever 37 forms a strap 43 on which is fitted, over a stud 45, the left-hand stop formed by a roller 44. A spring 46 engaging through one end a stud 47 rigid with the upper arm of the locking lever 37 and through its other end a stud 48 rigid with the driving friction box 13 urges said upper lever arm towards the left.

The lower arm of the left-hand locking lever 37 is offset towards the rear of the frame with reference to the upper arm of said lever. Its outer end is also provided with a special outline including a part OP forming an arc of a circle the center of which lies at B when the locking lever 37 and the damping or shockabsorbing lever 23 are in the positions illustrated in Fig. 6; said section OP is followed by a further section PQ formed by an arc of a circle having as its center D (Fig. 6) on the axis of the spindle 41, by a section QR which is rectilinear (Fig. 8), by a section RS formed by an arc of a circle the center of which lies at A when the locking lever 37 is in the position illustrated in Fig. 9 and lastly by a section SH constituted by an arc of a circle having its center at B when the lockinglever 37 and the damping lever 33 are in the positions illustrated in Fig. 11.

The right-hand locking lever 38 is arranged symmetrically of the left hand locking lever 37 and is carried in a similar manner by a spindle 51 screwed in a boss 50 of the same driving friction box13; symmetrically with reference to the lever 37, the upper arm of the right hand lever 38 is urged towards the right hand side of the frame by a spring 52 one end of which is attached to a stud 53 rigid with the lever 38 While its other end is attached to a stud 54 rigid with the friction box 13. The lever 38 is also provided with a strap 55 through which extends a stud 56 over which is revolubly mounted a roller 57. The ends of the lower arms of the locking levers on the right hand side and on the left hand side cross each other underneath the locking roller 29 (Figs. 2, 5, 8 and 14).

The device includes three friction stops, to'wit: a left hand stop 61, a right hand stop 62 and a splicing stop 63, said stops being provided with adjusting screws, respectively 64, 65 and 66 which are locked in position by corresponding safety nuts 64a, 65a, 66a. These three stops are carried in a similar manner and for instance the left hand stop 61 is adapted to slide transversely with reference to the friction box rod inside its stop carrier 67; it is held fast in the latter by a covering plate 68 secured to said carrier by the screws 69 (Figs. 3 and 4). A handle 71 rigid with the stop 61 allows positioning the latter either in its operative position, as illustrated in Fig. 4, i.e. in the path of the cooperating stop-carrying strap 43 or in an inoperative position shifted transversely outside said path as illustrated for the splicing stop 63 in Fig; 4.

The stop 61 is locked elastically in each of said two positions by an arrangement including a ball 72 housed inside a blind opening 73 formed in the stop carrier 67 and urged by a spring 74 into either of two conical recesses 75 and 76 formed in said stop 61.

The left hand stop carrier 67 is fitted on three control rods 77, 78 and 79 over which it may slide and it.

may be rigidly secured to the rod 78 by means of locking screws 81 (Figs. 1 and 3) screwed into said carrier 83 and provided with handles 91 and 92 through which it is possible to bring said stops selectively, respectively into their operative position and into their inoperative position, in which they are locked elastically by ball systems similar to the ball system illustrated for the left hand stop 61.

Fig. 1 shows furthermore a number of conventional parts of the knitting machine, adapted to cooperate in the formation of the meshes. These parts are: the needles 95, the needle bar 96, the jack sinkers 97, the forming plates 98, the plate carrier 99, the control bar 101, the knocking over plates 102, the sinker guide bar 103, the angle bar 164 on the plate carrier, the covers 105, the ticklers 106, the tickler control bars 107. In said Fig. l, the shock absorbing device is shown in a position for which the damping lever 23 extends vertically.

The operation of the shock absorbing device which has just been described is as follows: it includes, at the end of each sinking operation a four-period cycle consisting of a release of the cam, a damping, a positioning prior to the return of the friction box bar and a relocking of the cam.

Dur ing the sinking from the right hand side towards the left hand side of the frame, the friction box rod 14 drives the two friction boxes 13 and 14 from the right towards the left, said friction boxes being spaced by a distance defined by the connecting rod 31, the different parts occupying then the positions illustrated in Fig. 6. The damping lever 23 is held in its sloping position by the locking roller 29 engaging the section OP of the lower arm of the locking lever 37 subjected to the action of the return spring 46. The other locking lever 38 is held in the position illustrated, also by the lockingroller 29. The stop roller 44 is thus slightly spaced away from the damping lever 23.

Towards the end of the stroke of the yarn carrier rod 2, the outer end of the strap 43 of the locking lever 37 engages the left-hand stop formed by the screw 64, which provides for the beginning of the releasing stage.

The locking lever 37 thus urged back by the screw 64 pivots round its axis 41 until the stop roller 44 engages the damping lever 23 at the point W as illustrated in Fig. 7. At this moment, the point Q at the end of the locking lever 37 lies slightly underneath the straight line joining the center B of the locking roller 29 to the center D on the axis of the spindle 41 of said locking lever 37. The locking roller 29 is thus no longer in contacting relationship with the locking lever 37,

which releases the damping lever 23. This forms the end of the friction box releasing stage and the beginning of the damping stage which corresponds to the point E1 of the path followed by the carrier rod.

From this moment onwards, the driving friction box 13 slides over the friction box bar 14, this sliding being governed by conditions to be disclosed hereinafter and its movement is defined by the damping lever 23 of which one end engages the roller 44 through the point W (Fig. 7) while its other end is drawn along by the connecting rod 31 through the agency of the auxiliary friction box 34 which moves at a uniform speed with the friction box bar 14.

Consequently, the movement of the driving friction box 13 is damped as a consequence of the continuously varying ratio between the distance Ws of the contacting point W, on the one hand, from the horizontal line passing through the center A of the spindle 24 and, on

the horizontal line passing through the center B of the lockingroller 29-. The damping lever 23 and the locking lever 37 assume a gradualpivoting movement and pass through the, intermediate position illustrated in Fig. 8' before reaching the position illustrated in Fig. 9 for whichlthe damping lever 23 stands vertically. The drivingfriction, box 13 is then held fast, while the yarn carrier rod 2 engages its stop 7. This forms the end of{thev damping period which corresponds to the point E2 of the. path followed by the carrier rod and it forms also the beginning of the period during which the shock absorbing device is positioned for the return'of the friction box bar.

The auxiliary friction box 34 continues moving at the same uniform speed under the action of 'the friction box bar 14'and it continues producing a pivoting movement of the damping lever 23 (Fig. 10). Under the action of the spring 52, the other locking lever 38 pivots and the end of its lower arm remains in contacting relationship between the points R and Q with the lock ing roller- 29 until the moment at which the auxiliary friction box 34 is held fast as a consequence of the abutment of the locking roller 29 against the section SHof the outline of the locking lever 37 (Fig. 11). This forms the end of the positioning stage prior to the returnmovement and it forms also the beginning of the locking period.

The spring 52 provides then for a further rocking of the locking lever 38 (Fig. 12) until the section PQ' of the outline of the end of the lower arm engages the locking roller 29. This forms the end of the locking stage.

When the friction box bar 14 has finished its travel towards the left hand side and the mesh-forming movements have been produced, the friction box bar will start again fora sinking in a left to right direction and after the'sinking the shock absorbing operations are begun over again, however with a reversal between the parts played by the left hand locking lever 37 and the right hand locking lever 38.

The shock produced, at the end of the positioning stage before the return of the friction box bar, between the locking roller 29 and the locking lever 37 or 38. is' a reduced one, because the stress transmitted by the auxiliary friction box 34 is damped and is partly absorbed 'by the locking roller 29 which is made in the embodiment illustrated of plastic material, or by the material sold under the trade-name Celoron; butin all.

casesthe residual shock is not transmitted to theyarn carrier rod and is absorbed by the friction stop.

The graph appearing in Fig. 18 carries in ordinates the distances travelled over by the driving friction box 13 and in abscissae the times or more accurately the multiplesvT of-the times, i.e. the distances travelledv over by; the auxiliary friction box 34 moving without sliding at a-uniformspeed v over the friction box bar.

These distances aretgiven out by the positions of the;

center-X of the foot of the connecting rod 31 (Fig. 19-), which have been defined starting from the position of the center A of the spindle 24 of the damping lever 23,- account being-taken of the corresponding positions of the roller 44 forming a stop (the outer surface of the strap 43 extending over an arc of a circumference having as a center C which latter moves therefore along the veltical line C1C5.- Assuming Fe designates the maximum tractional stressv transmitted by the driving friction box and Pa the maximum tractional stress transmitted by the auxiliary friction box (Fig, 7), the following relationship is true:

'Two cases may thenbe considered:

(1) If .at, the beginning of the damping operation y 1 the, driving friction box 13. slides at the very beginning under the.action of the auxiliary friction box 34. The damping is normal'andiis illustrated by the curve drawn; in solid'linesat fh" in Fig. 18;

(-2)"If,,in contradistinction,. at the. beginning, of the damping stage y 1 theauxiliary friction box 35'slides at'the'beginning' of the; damping-period" under'theaction of the driving friction box 13untihthe-moment at which, by reason of the modifications'in' the distances WS and Wr, y drops underneath unityyfromthis moment onwards, the drivingfric tion box 13slides'in its*turn over thefriction box rod*'14- under the'action-ofthe auxiliary friction" box 34'; Thedamping whichis, illustrated by the curve fm-n'-p' drawn as adash line in Fig; 18-returns gradually to its normal shape, as' shown at m;

Itis-a veryeasy'matter to adjust the friction boxes 13 and 34-soastoobtain y 1; at'any rate, whatever'may be the value of y at the pointEl of the travel of the yarnkarrierrod, the-damping is obtained before the point E2 forwhich Ws -O.'

When the'friction box serves for drivinga yarn carrier rod for splicing' purposes-"and if, at the beginning, the' breadth of the'splicing' reinforcement is 'lower than the length providedfor damping, the splicing-stop 63 (Fig, 13')" isset'in' its operative position for the end'of the damping'stage at'a moment' at'which the damping lever 23 stands vertically, while the locking roller 29 whichis'in' contactingrelationship at the points R and R with'the' locking levers- 37"and"38 holds the latter in the position illustrated'in Fig; 14: The damping lever'23 rocks then until 'its-upper-partengages the stop roller 57' (Fig. 15). As-longasthe travel of' theyarn carrier rod is shorter than thele'ngthprovided for-damping, the damping lever 23 pivots between the position illustrated in Fig. l5 and the=position symmetrical thereof with reference to a vertical line passing'through the'pivotal axis of the dampinglever. The-travel of the"yarn carrier rod is entirely controlledby'the damping lever andno locking is obtained;

The operation at the tend of a toe is similar. The damping -lever'23 pivots=between the two positions of Figs. 16 and' 17" as defined'bythe outer stops 64 and 65 for the friotion=b'oxes. Thesp1icing stop 63 is collapsed and is positioned so as not todisturb the movement of the outer stops; as illustratedin- Fig; 4 for instance.

The shock 'absorbing device illustrated in Figs. 22't025 differs from thatwhich has just been described solely through the-particularshape given to the cam or damping lever, to the-locking levers and to the connecting'rod controlling said cam and also through a few small modifications-'in-" the relative position of these different parts. In these figures, thexsame reference numbers havebeen retained as-for those of the -above-described arrangements whenever they'are identical and the-reference numbers designating parts'theshape of which has been modified with'reference to the preceding embodiments have also been retained with the addition of sub-indexes.

In- Fig. 24; the cam 23a is-illustrated as having a symmetricaloutline including a' lower convex section IJ" coaxial with reference to its pivotal axis 24 and extending-betweenaits: two contactpoints with the two rollers 44 and' 47 on thelocking levers 37a and 38a when said cam'is-inxits=medialintermediate position. The two ends of saidsection I I,- are connected with each'other through the .convexrcurve'ssl'iNi and J'K' respectively, terminating with two small concave curvesNM and'KL, the two' outer ends1of .which are joined, so'as'to form a common point: at the uppersend of the cam.

The;connecting-.rod :31'aconnecting the auxiliary friction-.box 34owith the'lever 26a forming an'extension of" the cam 23a is bentdownwardly, as shown at 3112 (Fig; 22.) so that it maypass underneath the hub formed on. the 1e'ver'26d for=the dead point on the left hand side core r a 9 responding to the position illustrated in Fig. 25 whereby the cam 23a is adapted to pivot through one complete half revolution. A stud 16S, rigid with the main friction box 13 carrying the cam, prevents the lever 26a rigid with said cam from pivoting upwardly beyond the right hand side dead point illustrated in Fig. 22.

The ends of the locking levers 37a and 38a are coaxial with the corresponding pivotal axes 41 and 51 and when in their locking position they engage through their upper edge the lower surface of the hub on the lever 26a, as shown for instance for the lever 37a in Fig. 22 and for the lever 28a in Fig. 25.

In the embodiment illustrated, a depression 109 is formed in the hub of the lever 26a which allows reducing by a corresponding amount the bend given to the connecting rod.

Said shock absorbing device operates in a manner similar to that described hereinabove with the following similar stages corresponding to release, damping, positioning before the return of the friction box rod and locking. The sections JK' and I'N of the cam outline provide for the actual damping, while the sections K'L and NM' ensure the contacting. At the beginning of the damping, a slight sliding of the auxiliary box 34 is produced by the pivoting of the damping cam 23a through the agency of the stop roller 44 or 57 which is in contacting relationship with the corresponding section KL' or N'M of the cam, as the case may be, after which the normal damping is obtained under the control of the auxiliary friction box.

It is apparent that the stoppage of the auxiliary friction box at the end of the repositioning period before the return movement of the friction rod bar is obtained by the connection between the connecting rod 31a and the lever 26a carrying the damping cam 23a entering one of its dead points, so that said stoppage of the auxiliary friction box is obtained without any shock.

Obviously, my invention is by no means limited to the embodiments described and illustrated, given by way of mere exemplifications, and numerous modifications may be brought thereto by anyone skilled in the art with out widening unduly the scope of the invention as defined by the accompanying claims. Thus, for instance, the driving and the auxiliary friction boxes, instead of being carried by a commonfriction box bar, may be mounted on two parallel friction bars moving at the same speed.

What I claim is:

l. A shock absorbing device for the yarn carrier rod in flat lmitting machines of the Cotton type, comprising in combination with said yarn carrier rod, at least one friction box rod, a main friction box and an auxiliary friction box, each frictionally carried by a friction box rod, means for reciprocating said friction box rods longitudinally in synchronism, means drivingly interconnecting the yarn carrier rod with said main friction box, at least one stop for the yarn carrier rod defining the corresponding end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot over one of the following parts, the main friction box and the stationary member round an axis perpendicular to the direction of movement of the friction box rod, at least one cam stop carried by the other of said two parts, the main friction box and the stationary member, and adapted to make the cam rock when the main friction box reaches a point near the end of its reciprocatory travel in a direction for which the cam and cam stop move towards each other, means interconnecting mechanically the auxiliary friction box with the cam and wherethrough the rocking movement of said cam produces a shifting of the main friction box with reference to the auxiliary friction box and to the friction box rod carrying the latter and thereby a braking of the speed of the reciprocatory movement of said main friction box down to a substantially zero value,

at the moment at which the yarn carrier rod impinges against its stop and stops the main friction box.

2. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod with said main friction box, a stop for the yarn carrier rod defining each end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot over one of the following parts, the main friction box and the stationary member round an axis perpendicular to the direction of movement of the friction box rod, at least one cam stop carried by the other of said two parts, the main friction box and the stationary member, and adapted to make the cam rock when the main friction box reaches a point near the end of its reciprocatory travel in a direction for which the cam and cam stop move towards each other, means interconnecting mechanically the auxiliary friction box with the cam and wherethrough the rocking movement of said cam produces a shifting of the main friction box with reference to the auxiliary friction box and to the friction box rod carrying the latter and thereby a braking of the speed of the reciprocatory movement of said main friction box down to a substantially Zero value, at the moment at p which the yarn carrier rod impinges against its stop and stops the main friction box.

3. A shock absorbing device for the yarn carrier rod in fiat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod, at least one friction box rod, a main friction box and an auxiliary friction box, each frictionally carried by a friction box rod, means for reciprocating said friction box rods longitudinally in synchronism, means drivingly interconnecting the yarn carrier rod with said main friction box, at least one stop for the yarn carrier rod defining the corresponding end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot over one of the following parts, the main friction box and the stationary member, round an axis perpendicular to the direction of movement of the friction box red, at least one cam stop carried by the other of said two parts, the main friction box and the stationary member, and adapted to make the cam rock when the main friction box reaches a point near the end of its reciprocatory travel in a direction for which the cam and cam stop move towards each other, a connecting rod the ends of which are pivotally secured respectively to the auxiliary friction box and to a point of the cam at a point spaced from its pivotal axis, said connecting rod being adapted through the rocking movement of said cam to produce a shifting of the main friction box with reference to the auxiliary friction box and to the friction box rod carrying the latter and thereby a braking of the speed of the reciprocatory movement of said main friction box down to a substantially zero value, at the moment at which the yarn carrier rod impinges against its stop and stops the main friction box.

4. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod parallel with said yarn carrier rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod with said main friction box, a stop for the yarn carrier rod defining each end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot between two extreme angular positions over the main friction box round an axis perpendicular to the direction of movement of the friction box rod, a locking lever pivotally secured to the main friction box and including a section adapted to lockthe cam in one of its extreme positions during the major part of the travel of the main friction box with the friction box rod in a cor responding direction, a cam stop carried by the stationary member and adapted to engage the locking lever and rock same just before the end of the travel of the main friction box obtained by the impact of the yarn carrier rod against the corresponding cooperating stop and thereby release the cam, a cam follower revolubly carried by said locking lever and adapted to engage the cam under the action of said rocking movement of the locking lever to make said cam rock and produce thereby a relative movement between the friction boxes and consequently a shifting of the main cam-carrying friction box engaged by its follower over the moving friction box rod to damp the reciprocatory movement of the main friction box down to a substantially zero value at the moment at which the yarn carrier rod impinges against its stop and is arrested with said main friction box.

5. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod parallel with said yarn carrier rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod with said main friction box, a stop for the yarn carrier rod defining each end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot over the main friction box round an axis perpendicular to the rods between two extreme angular positions symmetrical with reference to a plane perpendicular to the rods, two locking levers pivotally secured to the main friction box to either side of the cam and including each two sections adapted to hold the cam selectively in its extreme angular positions during the major part of the travel of the main friction box in opposite directions of movement, two cam stops carried by the stationary member and each adapted to engage and rock the corresponding locking lever just before the end of the travel of the main friction box towards said cam stop to release said cam out of the extreme angular position in which it is held, a cam follower revolubly carried by each locking lever and adapted to engage the cam just after the beginning of the rocking movement of said locking lever to make said cam rock and thereby shift the main friction box with reference to the auxiliary friction box and friction box rod and damp the movement of the main friction box down to substantially zero value at the moment at which the yarn carrier rod impinges against its stop and stops said main friction box.

6. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod parallel with said yarn carrier rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod with said main friction box, a stop for the yarn carrier rod defining each end of the travel of the latter, a stationary member carrying said stops, a cam having two outline sections symmetrical with reference to a medial line and adapted to pivot over the main friction box round an axis perpendicular to the rods between two extreme angular positions symmetrical with reference to a plane perpendicular to the rods and passing through the medial line of the cam, two square-shaped two-arm levers pivotally secured to the main friction box to either side of the arm, a locking roller revolubly carried by the end of one arm of each lever for cooperation with the corresponding section of the cam outline, the other arm being provided with a recess, a locking roller revolubly carried by the cam at a point of its medial line spaced from its pivotal axis and engaging selectively the recesses in said levers for the two extreme angular positions of the cam during the major part of the travel of the main friction box in the corresponding direction of movement, a return spring urging elastically each locking lever into the position corresponding to engagement through its recess with the locking roller carried by the cam in its corresponding extreme angular position, two cam stops carried by the stationary member and each adapted to engage and rock the corresponding locking lever just before the end of the travel of the main friction box towards said cam stop to release said cam out of the extreme angular position in which it is held through engagement of the locking roller with the recess in said corresponding rocking lever, a cam follower revolubly carried by each locking lever and adapted to engage the cam just after the beginning of the rocking movement of said locking lever to make said cam rock and thereby shift the main friction box with reference to the auxiliary friction box and friction box rod and damp the movement of the main friction box down to substantially zero value at the moment at which the yarn carrier rod impinges against its stop and stops said main friction box, the cam returning then at the end of its rocking movement into its other extreme position for which the locking roller reengages the other locking lever.

7. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod parallel with said yarn carrier rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod with said main friction box, a stop for the yarn carrier rod defining each end of the travel of the latter, a stationary member carrying said stops, a cam adapted to pivot between two extreme angular positions over the main friction box round an axis perpendicular to the direction of movement of the friction box rod, a locking lever pivotally secured to the main friction box and including a section adapted to lock the cam in one of its extreme positions during the major part of the travel of the main friction box with the friction box rod in a corresponding direction, a cam stop carried by the stationary member and adapted to engage the locking lever and rock same just before the end of the travel of the main friction box obtained by the impact of the yarn carrier rod against the corresponding cooperating stop and to thereby release the cam, a cam follower revolubly carried by said locking lever and adapted to engage the cam under the action of said rocking movement of the locking lever at a point the distance of which from a line parallel with the rods and passing through the pivotal axis of the cam decreases gradually down to zero to produce a gradually decreasing torque to make said cam rock and produce thereby a relative movement between the friction boxes and consequently a shifting of the main cam-carrying friction box engaged by its follower over the moving friction box rod to damp the reciprocatory movement of the main friction box down to a substantially zero value at the moment at which the yarn carrier rod impinges against its stop and is arrested with said main friction box, the continuing movement of the cam follower beyond said line passing through the pivotal axis of the cam urging the cam into its other extreme angular position.

8. A shock absorbing device for the yarn carrier rod in flat knitting machines of the Cotton type, comprising in combination with said yarn carrier rod a friction box rod parallel with said yarn carrier rod, means for producing a longitudinal reciprocatory movement of said friction box rod, a main friction box and an auxiliary friction box both frictionally carried by said friction box rod, means drivingly interconnecting the yarn carrier rod 

